Tectonostratigraphic framework in the eastern Korean continental margin, East Sea: Implication for evolution of the Hupo Basin

Abstract

Integrating seismic interpretation facilitates the discernment of tectonostratigraphic evolution in the eastern Korean continental margin, East Sea. The sedimentary succession of this margin is divided into three major seismic units based on distinct unconformities. These unconformities and their associated seismic characteristics indicate that the eastern Korean continental margin has experienced four evolutionary stages through extensional and subsequent two‐phase tectonic inversions. Early Miocene back‐arc opening of the East Sea triggered the extension of NNW–SSE and N–S trending rifts, resulting in non‐marine to deep‐marine deposition of typical rift‐related linked sedimentological systems in the eastern Korean continental margin. In the early Late Miocene, changes in plate motion and the subduction mode of the Japanese island (NW–SE compression) caused the positive inversion of extensional fault‐bounded half‐grabens in the eastern Korean continental margin, and the Hupo Basin was likely created by the regional flexural response. During this depositional period, hemipelagic sedimentation accompanied by episodic gravity‐controlled slope failures was predominant in the deep‐water environment. The subsidence of the Hupo Basin was enhanced by crustal shortening (E–W compression) that was induced by subduction initiation at the western margin of the Ulleung Basin during the late Early Pliocene (ca. 3.8 Ma). At that time, sedimentary environment gradually became shallower with time and coarse‐grained terrigenous input into the Hupo Basin began so that shallow‐ to deep‐marine sedimentation occurred. In the Quaternary period, the uplift of the Hupo Bank and coeval subsidence of the Hupo Basin were maintained by continued compressive neotectonics. The shallow‐ to deep‐marine deposition continued, but greater quantities of coarse‐grained terrestrial sediment were transported into the Hupo Basin due to combined effects on tectonics and eustasy. Based on the tectonostratigraphic reconstruction developed in this study, we propose that the Hupo Basin is likely a Late Miocene–Quaternary compression‐related basin induced by crustal or thrust loading.

Seismic stratigraphy and structural evolution of the South Korea Plateau, East Sea (Sea of Japan)

“…SF2 exhibits variable amplitude and poor‐to‐moderate continuity with deformed and/or disrupted configurations. Based on these internal/external seismic features and its spatial distribution, SF2 is interpreted to represent fan‐deltas and slope‐aprons deposited in a non‐marine to shallow‐water environment (Park et al, 2022; Zhou et al, 2014). SF3 displays low‐to‐moderate amplitude and poor continuity with a lens‐shaped external form.…”

“…Based on its seismic characteristics, SF5 is interpreted to reflect hemipelagic sediments deposited under a quiescent, settling environment (Kim, Yi, et al, 2020; Kim, Yoo, et al, 2020; Sangree & Widmier, 1977). SF6 is characterised by moderate‐to‐high amplitude and good continuity, with well‐stratified configurations, interpreted as hemipelagic sediments interbedded with sandy turbidites (Joh & Yoo, 2009; Park et al, 2022). Finally, SF7 displays an intermediate seismic feature between SF3 and SF6.…”

“…• Moderate-to-high amplitude, high frequency, good continuity • Parallel to divergent reflection configuration Lacustrine deposits (Cukur et al, 2015;Zhou et al, 2014) • Variable amplitude, poor-to-moderate continuity • Deformed/disrupted configuration Non-marine to shallow water, fandelta, slope-apron (Park et al, 2022;Zhou et al, 2014) • Low-to-moderate amplitude, poor continuity • Chaotic internal character with lensshaped external form Mass transport deposits (MTDs; Cukur et al, 2015;Kim, Yoo, et al, 2020;Lee & Suk, 1998) • High amplitude, poor continuity • Complex, irregular reflections Volcanic sills and lava flows (Cukur et al, 2015;Kim, Yoo, et al, 2020;Lee et al, 2001) • Low amplitude, good continuity • Parallel to divergent configuration Hemipelagic sediments Kim, Yoo, et al, 2020; Moderate-to-high amplitude, good continuity with well-stratified reflections Hemipelagic sediments interbedded with sandy turbidites (Joh & Yoo, 2009;Park et al, 2022) • Low-to-high or variable amplitude, weaklystratified, moderate continuity • Intermediate character between SF3 and SF6…”

“…Mixed MTDs and turbidites/hemipelagic sediments (Joh & Yoo, 2009;Kim, Yoo, et al, 2020;Lee & Suk, 1998;Park et al, 2022)…”

Analogue modelling of basin inversion: a review and future perspectives

“…Inverted basins are very common geological features and are found in multiple locations, for instance the North Sea area (Lamplugh, 1919;Glennie and Boegner, 1981;Nalpas et al, 1995;Evans et al, 2003;De Jager, 2003;Hansen et al, 2021), the Pyrenees and European Alps (Pfiffner, 1993;Ziegler et al, 1995;Kiss et al, 2020;Mencos et al, 2015;Lescoutre and Manatschal, 2020;Musso Piantelli et al, 2022), the Atlas Mountains (Vially et al, 1994), Iran (Boutoux et al, 2021), the Araripe Basin in northeastern Brazil (Marques et al, 2014), the Andes (Ferrer et al, 2022b, and references therein), offshore of Korea (Park et al, 2021), and China (Yu et al, 2021), as well as many other places around the globe (Letouzey, 1990;Lowell, 1995;Iaffa et al, 2011;Gibson and Edwards, 2020;Bosworth and Tari, 2021;Dooley and Hudec, 2020).…”